Green push for Granny Smith

South African giant Gold Fields is the latest miner in Australia to turn to renewable energy, at its Granny Smith gold mine near Laverton, giving the green tick to a hybrid solar-gas power plant described as one of the world’s largest renewable energy microgrids.

Up to 30 people will be on site at the peak of construction, which will see 20,000 solar panels installed to complement Granny Smith’s existing gas-fired power station.

The 8MW solar installation will be backed up by a 2MW/1MWh battery system and reduce the mine’s fuel consumption by up to 13 per cent, the equivalent of taking 2000 cars off the road.

Construction at Granny Smith, about 20km south of Laverton, is expected to start in May, with the microgrid to be up and running by the December quarter.

The installation is the latest move in the gold producer’s shift to clean up its energy supply after dumping diesel when Aggreko installed its gas-fired plant in 2016 following the construction of the Eastern Goldfields Pipeline.

It will expand Aggreko’s power-generating capacity at Granny Smith to 24.2MW, with the 1100m-deep Wallaby underground deposit and its power requirements continuing to grow.

A desire to shift to more sustainable power was behind the decision to approve the project, but Gold Fields Australasia executive vice-president Stuart Mathews also sees potential cost savings from the transition to renewable energy.

“As we stand today we have a minimum of eight years (at Granny Smith) and still have no end in sight as long as we invest in exploration in the mine, so it has long life and that’s why we have confidence to commit to something like this,” he said.

“As we get deeper we have to invest in getting more power down that mine.

“We had an opportunity to go a bit new age by using solar, which is even a further reduction in the cost of energy for the site, and power is one of our biggest costs on a mine site.”

About half of the power supply at Granny Smith is required for the Wallaby mine, while the other half will be used to run its 3.2 million tonne a year processing plant and camp.

Gold Fields has followed ASX-listed miners Sandfire Resources and Independence Group in the transition to renewable energy.

Sandfire commissioned a 10.6MW solar panel installation at its DeGrussa copper-gold mine in the Mid West in 2016.

A solar addition to the diesel-fired power plant at Independence Group’s Nova nickel mine in the Goldfields has also been announced.